repack
Question: in IDS 11.50, will a table REPACK merge a two-extent table down to one extent? Answers: not by itself — repack only shifts rows toward the start of the table; you must follow it with SHRINK, which can release whole extents left empty, so success depends on row count and free space. The extent-merging DEFRAGMENT feature only exists from 11.70 onward (with fragmentation/rolling-window options suggested as alternatives). A follow-up asked whether DEFRAGMENT logs and risks long transactions; IBM's John Miller and Art Kagel confirmed it logs but works in small mini-transactions, so long transactions aren't a concern.
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In IDS11.5 , I want to to do reorg. if a table has 2 extent,Do repack can reduce the extent to 1? thanks for your time.
No, maybe. Repack only "shifts" the records to the "beginning" of the table. This per si, will not free any extent. But after you do a repack, you can "shrink". Shrink will try to release the space left free (full extents) by repack. So, if the repack leaves your second extent free the shrink will release that extent. This will depend on the number of records and the "free space" in the first extent. You may be confusing repack with the defragment task available in 11.7. This will in fact try to merge existing extents into one (depends on size and free space in the dbspace(s)). Regards. On Tue, Sep 3, 2013 at 10:15 AM, CHUAN LU <luchuan@cn.ibm.com> wrote: > In IDS11.5 , I want to to do reorg. if a table has 2 extent,Do repack can > reduce the extent to 1? > > thanks for your time. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently... --047d7b6dcb7cf8c0f104e577920b
Sometimes. Art On Sep 3, 2013 4:16 AM, "CHUAN LU" <luchuan@cn.ibm.com> wrote: > In IDS11.5 , I want to to do reorg. if a table has 2 extent,Do repack can > reduce the extent to 1? > > thanks for your time. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --089e011769157a8cf804e578d080
Hello. Two extents is not a big enough number, unless you have several gigs in size, for each of them. In that case, your best approach should be fragmenting the table, in order to avoid using the old (coldest) data. Remember that 11.70 has great support for new kinds of fragmentation strategies, and you should consider an upgrade as soon as possible. 12.10 has even more automated features for rolling windows fragmentation, which fully automates your allocation/deallocation of old and new data. Informix 11.70+ has also a defragment table/partition, which can always reduce your extent(s) number(s) to only one. That is not always true for 11.50, as said before. Hope it helps. Regards. Alexandre Marini IBM Informix Certified Professional v10 / v11.50 / v11.70 / v12.10 IBM Information Management Informix Technical Professional IBM Infosphere DataStage Technical Professional Informix Senior DBA - Orizon Brasil BRIUG website administrator Informix independent consultant > To: ids@iiug.org > From: art.kagel@gmail.com > Subject: Re: repack [31329] > Date: Tue, 3 Sep 2013 07:16:07 -0400 > > Sometimes. > > Art > On Sep 3, 2013 4:16 AM, "CHUAN LU" <luchuan@cn.ibm.com> wrote: > > > In IDS11.5 , I want to to do reorg. if a table has 2 extent,Do repack can > > reduce the extent to 1? > > > > thanks for your time. > > > > > > > > > ******************************************************************************* > > Forum Note: Use "Reply" to post a response in the discussion forum. > > > > > > --089e011769157a8cf804e578d080 > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. >
In IDS11.7， Do defragment exent write the logical log? if a table has huge data,that might lead to the long transaction? thanks for your time.
Defragment extents does the work in small mini-like trans= actions to ensure long transactions are avoided. John = F. Miller III STSM, Lead Architect miller3@us.ibm.com 503-747-136= 6 IBM Informix Dynamic Server (IDS) -----ids-bounces@iiug.org wrote: ----- >To: ids@iiug.org= >From: "CHUAN LU" >Sent by: ids-bounces@iiug.org >Date:= 09/03/2013 10:30PM >Subject: Re: RE: repack [31347] > >= In IDS11.7， Do defragment exent write the logical log? if a &= gt;table has huge data,that might lead to the long transaction? >tha= nks for your time. >*************************************************= ******************** >********** Forum Note: Use "Reply" to post a= response in the >discussion forum. =
Defragment does use logical log space, but it is performed using small transactions of a small number of pages at a time. Long transactions are not an issue. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Wed, Sep 4, 2013 at 12:56 AM, CHUAN LU <luchuan@cn.ibm.com> wrote: > In IDS11.7， Do defragment exent write the logical log? if a table > has > huge data,that might lead to the long transaction? > > thanks for your time. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --047d7b47249ce7cbc804e591fd36